In a system having an imaging device for acquiring an image and a display device for displaying the image acquired with the imaging device, the imaging device acquires a subject under imaging conditions set and generates an image signal, and the display device displays an image based on the image signal in accordance with display conditions set. However, since the imaging conditions of the imaging device are set separately from the display conditions of the display device, unless matching is established between the imaging conditions and the display conditions, the display device cannot display the image appropriately. Accordingly, there is an image display system that displays an image appropriately by altering display conditions in accordance with the imaging conditions at the time when the imaging device takes a picture of a subject (Patent Document 1).